/*
 * Copyright (C) 2011-2013 Markus Junginger, greenrobot (http://greenrobot.de)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.mlizhi.base.dao.query;

import com.mlizhi.base.dao.AbstractDao;
import com.mlizhi.base.dao.DaoException;
import com.mlizhi.base.dao.InternalQueryDaoAccess;

/**
 * A repeatable query returning entities.
 * 
 * @author Markus
 * 
 * @param <T>
 *The enitity class the query will return results for.
 */
// TODO support long, double, blob types directly
abstract class AbstractQuery<T> {
protected final AbstractDao<T, ?> dao;
protected final InternalQueryDaoAccess<T> daoAccess;
protected final String sql;
protected final String[] parameters;
protected final Thread ownerThread;

protected static String[] toStringArray(Object[] values) {
int length = values.length;
String[] strings = new String[length];
for (int i = 0; i < length; i++) {
Object object = values[i];
if (object != null) {
strings[i] = object.toString();
} else {
strings[i] = null;
}
}
return strings;
}

protected AbstractQuery(AbstractDao<T, ?> dao, String sql, String[] parameters) {
this.dao = dao;
this.daoAccess = new InternalQueryDaoAccess<T>(dao);
this.sql = sql;
this.parameters = parameters;
ownerThread = Thread.currentThread();
}

// public void compile() {
// // TODO implement compile
// }

/**
 * Sets the parameter (0 based) using the position in which it was added during building the query.
 */
public void setParameter(int index, Object parameter) {
checkThread();
if (parameter != null) {
parameters[index] = parameter.toString();
} else {
parameters[index] = null;
}
}

protected void checkThread() {
if (Thread.currentThread() != ownerThread) {
throw new DaoException(
"Method may be called only in owner thread, use forCurrentThread to get an instance for this thread");
}
}

}
